Dog Development Stages Explained

three dogs at different development stages

We’re going to look at the different developmental stages your dog will go through as they mature, alongwith how to navigate each stage of your dog’s life so you’re prepared for the ride. 

Let’s dive in and explore dog behaviour by age, so you can see where you’re at in the journey and what you have to look forward to! 

6 life stages of a dog

  • Neonatal: birth – two weeks old
  • Transitional: 2 – 4 weeks old
  • Critical Learning: 3 – 16 weeks old
  • Adolescence: 5 – 30 months old
  • Adult: 2 – 7 years old
  • Senior: 7 years+

Early Puppy Development Stages

Between 3- 5 weeks puppies start to become aware of their surroundings and have the ability to develop a relationship with people. This is the period where puppies get familiar with the day-to-day noises of a regular household such as TVs, vacuum cleaners, telephones, etc.

For almost all puppies, they’re with their breeder at this stage in their life. Choosing a good breeder who is putting time and effort into early puppy socialisation makes a big difference in this important phase of a dog’s life.

Puppy socialisation period (the critical learning stage)

The period from about 4 to 16 weeks is one of the most important in your dog’s life, it’s known as the ‘socialisation window’. This is the stage in your puppy’s life when they’re sponging up life lessons and forming opinions on everything around them. 

During this formative period, the things your puppy experiences will have a huge impact on the development of their personality and behaviour. 

puppy socialisation

Learn more about how to socialise your puppy in three easy steps here. 

As an owner to many rescue dogs, I will reassure you that there is some flexibility here! Many of my rescues had zero socialisation before they came to me, if you met them now you’d never know they had any problems. 

If you had no influence on your dog’s life during the socialisation period, you can still turn things around. 

Puppy Fear Periods

During a fear period, puppies become more sensitive and aware of the world around them. There are three main fear periods in a dog’s life. 

  • 8-12 weeks
  • 4-9 months
  • 12-24 months

During these fear periods, a dog may become concerned or unsure about new objects or experiences that they previously enjoyed. 

If they become too sensitive towards something, it tends to imprint into a young dog’s mind which can affect their behaviour for the rest of their life.

Signs your puppy is going through a fear period

The signs your dog is experiencing a fear period can vary greatly but the common theme will be that it’s a sudden onset. This is commonly in response to normal day to day things that were previously a non-event. 

  • Acts afraid of people, animals, and/or unfamiliar objects
  • Startles easily at noises or sudden changes
  • Barks and backs away from new things
  • Often we see fearful body language, including pinned ears or a tucked tail
  • Shows a dramatic behavioural change after a single unpleasant event

puppy development stages

How to help your puppy through a fear period

Typically fear periods last just a few weeks. How you support your dog through this tricky developmental period will have a big impact on how it affects your dog. 

Here are my top tips for supporting your puppy through fear periods. 

  • Allow them space from the scary stuff
  • Don’t tell your puppy off for being scared
  • Go at your puppy’s pace
  • Pair scary stuff with good things – aka treats or play
  • Expose your puppy to things little & often 

The worst puppy age!

The most difficult stage of puppy development is when your dog hits adolescence. This period will vary by age, but typically begins around 5 months old and can last until around 30 months old.

This is the most difficult phase in your dog’s life. It’s not because you’re doing anything wrong, it’s hard for even the most experienced dog trainers. 

Signs your puppy is entering adolescence

  • Not following instructions
  • Running away from you when off lead
  • Chasing wildlife
  • Male dogs will be more interested in scent and spend more time sniffing 
  • Increase in marking on walks
  • Increase in sociability with other dogs or people 
  • You may see altercations between entire male dogs

During adolescence, your dog is experiencing dramatic hormonal changes and a reorganisation of the brain. Their brain matures from the back to the front, so the back part of your dog’s brain will develop faster than the front. 

The communication between the frontal cortex and amygdala (the back part of your dog’s brain) is broken down during the adolescent phase. 

adolescent dog behaviour

The amygdala is fully formed, which leads to fight or flight behaviour and a lack of focus. 

Your dog’s frontal lobe allows them to make sense of training, and it’s not fully formed during adolescence. 

This explains why you may find yourself struggling with difficult behaviour during this period in their lives.  

During adolescence, your dog is becoming sexually and socially mature. They are also realising what they were bred for. 

This is also the stage where most dogs are likely to be rehomed.

A Dog’s Trust study in 2005, found that over 50% of dogs relinquished for rehoming were between 5 months and 3 years of age.  The adolescent stage! 

Surviving adolescent dog behaviour struggles

During the teenage dog phase, you need to cut both your dog and yourself some slack. You might find yourself constantly embarrassed and frequently apologising for your dog’s behaviour.  

All is not lost, remember this is a normal stage in your dog’s development. 

  • Take your training back to basics
  • Use management to set you both up for success
  • Cut yourself some slack
  • Know you haven’t ruined your dog 
  • Limit self rewarding behaviours 
  • Talk to people (don’t struggle alone)

Management means using things like a long line training lead for recall or picking your walking spots carefully. Stay away from busy walking spots or wildlife heavy areas for example. 

You’ll find some great tips in my blog on how to teach your dog to ignore other dogs. 

When is a dog not a puppy anymore?

When your dog matures will vary by breed, and is linked to when your dog leaves the adolescence phase. 

Smaller breeds will mature at around 20 months old. Larger breeds will mature and calm down between around 24-30 months of age. 

At this point, your dog is entering the adult dog developmental stage, which is a welcome relief for everyone! 

Adulthood – the good years!

This is the moment you’ve been waiting for! By the age of 3yrs old most breeds are fully grown and their brains are fully developed. 

Your dog is better at making decisions, following instructions and will be less inclined to seek social interactions with people and dogs they don’t know. Your dog finally should have a solid understanding of how you expect them to behave. 

Hurrah – you’ve entered the development stage that you’ve been waiting for. Enjoy it! 

two adult border terriers in a bed

You might find your dog becomes a little more aloof with strangers and dogs they don’t know. In fact, you know those dogs you see out on walks that you wish your dog would behave like? Yeah, they’re probably over 5 years old! 

If you’re having problems with your dogs behaviour from 3 years and above, I recommend contacting a dog trainer or behaviourist for support. You can reach out to me here.

Senior Dog Life Stage

This stage in a dog’s life can sneak up on us. It’s a lovely stage and also a sad stage at times. From around the age of 7 years old, your dog is entering their golden years. 

If you have a large breed, the senior life stage can set in sooner as their life spans can be shorter. 

senior dog behaviour

Most of us don’t notice our dog ageing as it happens so gradually, but there are things we can do to help them out and make it easier for them. 

  • Keep your senior dog active. Inactive dogs lose muscle mass, by keeping them active they will keep it
  • Visit new walking locations to provide enrichment
  • Protect your dog’s joints by reducing opportunities to slip or jump. Use rugs at home, lift them in and out of vehicles
  • Keep your dog’s weight down. Include regular vet visits and check blood samples to stave off problems
  • Consider pain relief if needed  
  • Be aware of changes in their behaviour and don’t just put it down to being old

Canine Arthritis Management is a brilliant organisation that shares a lot of valuable information for dogs at every life stage. I’d highly recommend having a read and learning how to protect your dog’s joints through lifestyle choices. 

The webinar every dog owner should watch

Understanding your dog through every stage of their life is something that makes life both easier and happier for you and your dog.

Get instant access to a full 90 minute webinar exploring each stage in more detail, with plenty of real life examples to help you navigate them successfully. 

When you understand and meet your dog’s needs through every life stage, everything else is so much easier… yes, even the teenage phase! 

Get instant lifetime access here for just £10 👇

Read Next:

5 fun recall games for dogs who don’t come back

Successful puppy socialisation in 3 easy steps

Dog walking etiquette – how to have the best behaved dog in town

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Becky Milne East Coast Dog Training with Border Terrier

Hi, I’m Becky

I’m an ethical and positive dog trainer who wants to help you create a fantastic relationship with your dog.

I offer fun and effective dog training that makes you WANT to train.